In some cases it might be wise to spin down a hdd in order to save power, reduce noise or whatever.
Most people will tend to let the system manage spin up/down of a hard drive, and mostly this feature is used on portable laptops to save battery energy.
On an always-on desktop machine it is probably wise to keep the system disk spinning. Anyway, if your scenario includes a second drive, for example a disk you use for seldomly accessed videos or data it could be a good idea to switch off that drive while it is not being used over hours.
On linux you can chose between an number of tools to get access to the on/off switch of your drive:
- hdparm is a powerful drive tool and can be used to spin down and spin up a hdd. You can configure it to do so after a period of inactivity, for example with
hdparm -S60 /dev/sda
or you might instruct it to immediately issue the up/down command on a device.
The -y switch will put a drive in standby mode, -Y puts a drive to sleep. Refer tohdparm's manual for detailed instructions.
- sg_start from the sg3-utils package can power down a drive.
- spindown is a flexible daemon that can be configured to monitor and spin down drives according to a configurable scheme. It relies on sg_start.
Windows, to my knowledge, does not expose direct means to easily turn off a hdd. The Windows port of hdparm might help you here.
Please be advise that there are opposing views if it is wise to continually power up and power down a drive. Starting/stopping may do more harm to the drive than the savings in power or reduction of noise is worth it. Still, if spin-ups/spin-downs will hurt your drive relates to their age, their type and your turn on/turn off cycles lengths.